Process for preparing substituted piperidones



Patented Apr. 25, 1950 PROCESS FOR PREPARING SUBSTITUTED PIPERIDONES Herman A. Bruson,

Rydal,

and Warren D.

Niederhauser, Philadelphia, Pa., assignors, by mesne assignments, to Rohm & Haas Company, Philadelphia, Pa., a corporation of Delaware No Drawing. Application March 27, 1946, Serial No. 657,538

8 Claims. (Cl. 260-293) This invention relates to hydrocarbon-substituted piperidones. It deals with a process for the preparation of these compounds by reacting together ammonia, a gamma-formyl-carboxylic acid, or one of its. amides, or esters, and hydrogen in the presence of a hydrogenation catalyst.

The products obtained have the general formula R I HOOOOH:CHzG-CHO t, particularly where R and R are one or more hydrocarbon groups, particularly alkyl groups of one to four carbon atoms each as in Such aldehydo acids, their amides, and their esters are readily obtainable, for example, through the reaction of acrylonitrile and aldehydes followed by hydrolysis. Further details concerning this method of preparation of these starting materials may be obtained from U. S. Patents Nos. 2,342,607 and 2,353,687. In place of the acids shown above, there may be used their esters, such as their methyl, ethyl, propyl, or butyl esters.

The reaction may be carried out at temperatures from just above room temperature (3040 C.) up to about 200 C. under hydrogen pressures slightly above atmospheric to several thousand pounds per square inch. Cne of the aldehydo acids, or a functional derivative thereof, is mixed with at least an equivalent of ammonia. Advantageously an inert solvent such as alcohol or water is used. A hydrogenating catalyst is added thereto and the system flooded with hydrogen.

The nature of the catalyst added helps determine the optimum temperature of the reaction. With more active catalysts, such as finely divided platinum or palladium, reaction occurs over the lower range of temperatures. Other catalysts, such as finely divided nickel or copper chromite, require generally higher temperatures.

The following examples illustrate the invention; the parts indicated being parts by weight.

Example 1 CzHs' CH! /([3 CH: 0,11. CH1 /('J=O NH Anal.Calculated for CBHl'lNO: C, 69.7; H, 11.0; N. 9.03. Found:C, 69.78, H, 10.94; N, 8.69. Additional product can be recovered from the mother liquors to give an almost quantitative yield.

f f ieu'l Example 2 C2H5 on: a

\C CH:. 0.11.4615. 6e25,??? un V In an" analogous'manner other gamma formyl "carboxylicacids, or} functional derivatives such 'as 'their esters; maybe reacted 'withi ammonia and h ro ni Pla e ih ee u s i 19 amm ni used w r em l ise m be used. Othersolv ents, such as ethyl alcohol, isopropanoL-tert-butyl alcohols or dioxanes, and

1 i m ba ee- The productsl of; this invention' are useful as intermediatesin the; preparation of delta amino Qcarboxylic acids and derivatives thereof through splitting of the ring. The products themselves have strychnine-like' properties.

We claim: l. A process for preparing pip'eridones of the "formula 4; Q It CH1 (i= whereinR and represent members. of the class PQR i I f hydr g .mo o a t.h d rh groups, and, when taken jointly, a saturated divalent hydrocarbon: "chain'which forms a cycle .witnthe rbqn atomi n ns th s erouph h comprisesmixingand reacting together in the presence of a hydrogenation catalystand between 30 and 20011;.'annnonia, hydrogen, and a memv.loer; of the class consisting of gam ma-formyl monocarboxylic acids and their esters with saturated monohydric aliphatidalcohols of not over f o r ca h nat ms- Q 3 a se v r era s i rif h M32 I wherein R and Rf are .alkyl groups, which comprises reacting together'between 30 and 200 C. ammonia, hydrogen} and an acid of the formula in the p es nce o a y genation catalyst? The reaction mixture was filtered from 4 3. A process for preparing piperidones of the formula 'wherein Brand R are alkyl groups, which com- 10"prises reacting together between 30 and 200 C. ammonia, hydrogen, and an acid of the formula HOOQ-CHzCHr-C-CHO 311111.115 presenceof active nickel.

4. A process for preparing piperidones of the formula "*which comprises mixing and reacting together between and 200 C. ammonia, hydrogen, and an acid of the formula- C2115 H0OQ CH2QHa-CCH0 2H5 in the presence of active nickel.

5. A process for preparing piperidones of the formula a 0211s CH2 o \OH2 CiHo lHz J=O \N which comprises mixing and reacting together between 30 and 200? C. ammonia, hydrogen, and an acid of the formula C2135 nooo-omom- -ono in the presence oflactive nickel. 6. Compounds of the formula wherein R and-R'are alkyl groups of one to four carbon atoms each.. i I

7. A compound'of the formula @2115 CH: -o CHa" CaHa JHz 1:0

8. A compound of the formula CH: sate re-1 N HERMAN A. BRUSON. WARREN D. NIEDERI-IAUSER.

(References on following page) 6 Name Date Lazier Nov. 26, 1940 Bolt Jan. 7, 1941 Drossbach et a1. Jan. 20, 1944 Bruson et a1. Feb. 22, 1944 OTHER REFERENCES 'Wallach: Annalen (Liebigs), vol. 324, p. 289 

1. A PROCESS FOR PREPARING PIPERIDONES OF THE FORMULA 